ABSTRACT
Corn starch is a widely used polysaccharide known for its biodegradability, availability, and costeffectiveness. However, its natural properties often limit its industrial applications due to poor solubility, low stability, and limited functionality. This project aims to improve these properties by chemically modifying corn starch with Monochloroacetic acid (MCA) at differentratios. The goal is to determine how varying MCA ratios impact the starch's physicochemical properties and optimize it for specific industrial uses. In this study, corn starch was modified by reacting it with MCA at four different concentrations: 2.50g, 6.60g, 15.0g, and 40.0g (w/w). The reactions were carr:ied out under controlled conditions to ensure consistent results. The modified starches were then analyzed to measure the degree of substitution (DS), which indicates the extent to which hydroxyl groups in the starch molecules were replaced by Carboxymethyl groups. Additionally, the cold water solubility of each modified starch was measured. The findings revealed significant differences in the properties of the modified starches based on the MCA ratio. Higher MCA ratios resulted in a higher degree of substitution, indicating more extensive modification of the starch molecules. This increased modification led to notable changes in the starch's crystallinity, solubility, and thermal stability. Cold water solubility tests showed that the 2.5g MCA-modified starch had a solubility of 26%, the 6.60g MCA-modified starch had a solubility of 22%, the 15.0g MCA-modified starch had a solubility of 15%, and the 40.0g MCA-modified starch had the lowest solubility at 7%. These changes in solubility were accompanied by enhanced thermal stability and altered crystallinity. Modified starches demonstrated improved solubility and thermal stability compared to unmodified corn starch. In particular, starch modified with 2.50g MCA showed the highest solubility and stability, making it suitable for high-performance applications in industries such as pharmaceuticals and food. Additionally, the modified starches exhibited enhanced thickening and gelling properties, which are advantageous for various industrial formulations. In summary, modifying com starch with Monochloroacetic acid at different ratios effectively enhanced its functional properties. The extent of these enhancements was directly related to the concentration of MCA used. This study offers valuable insights into optimizing corn starch for a range of industrial applications, demonstrating the potential of chemical modification to expandthe utility of this abundant biopolymer. Future research will focus on scaling up the modification process and assessing the performance of the modified starches in practical applications, ensuring their economic and environmental viability.
